Author Topic: Resurrecting A Very Sad 1975 CB550  (Read 4523 times)

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Offline campbmic

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Resurrecting A Very Sad 1975 CB550
« on: January 05, 2010, 12:41:29 PM »
Bike: 1975 CB550K

Current Questions:

#1) So I have decided to rebuild the bike from the ground up! I've never planned an engine rebuild before and would really like a nice list of things to check/replace that I can go through to plan my build.  

#2) Do you guys feel that for my trip it would be necessary to check out the bottom end? I didn't really have any transmission issues when I was able to ride it. I'm planning cleaning out the fuel pump filter but thats about it so far unless anyone has any advice.

#3) Furthermore, I really want to shine the crap out of the cases to make the engine look brand new. How can I do this without splitting the cases?


Background
This summer I plan on riding my bike from Dallas, Texas to Cancun for a friend's wedding. I want to have the bike in tip top shape just like it came out of the factory so I don't get stranded and end up having to leave the her in Mexico.  So I have about 6 months or so to dedicate to the rebuild.

I drove an hour to check out this bike. When I arrived the owner told me he got the bike  in a trade and it would turn over but it wouldn't start. I checked and the fuel shutoff valve was in the off position. So after talking him down to $200 I carted the bike away! This was in November of 2009







After I got the bike home I turned the fuel valve on and tried to start it to no avail. I disconnected the tank and saw that the petcock and carb lines were completely stopped up with dirt. It was like someone tried to use dirt as gasolione  ???. Anyways, after cleaning the tank the bike still wouldn't fire. I checked and the coils weren't getting any electricity so I ran a straight wire from my + terminal to the coils and it fired right up! I rode the bike about twenty miles like this and then drug it back home after my back tire went out.

It was sounding very bad and would cut out every 4 miles or so. So I proceeded to clean out the carbs, I tried to bench sync them the best I could but still have work to do. The bike didn't come with an air box so after I put the carbs back on the bike it ran very wacky. She was now leaking fluid out of the cylinder #1 exhaust head (the PO put a crappy 4 into 1 without any exhaust gaskets) she also kept draining batteries and would die every mile or so and I would have to push it home.

So I have decided to rebuild the bike from the ground up! I've never planned an engine rebuild before and would really like a nice list of things to check/replace that I can go through to plan my build.

Thanks for any and all help!
« Last Edit: January 10, 2010, 11:16:36 PM by campbmic »
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traveler

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Re: Resurrecting A Very Sad 1975 CB550
« Reply #1 on: January 05, 2010, 04:45:38 PM »
Good luck!

200 bucks for a bike that runs.  If it has a clear title, and frame isn't bent...it can be saved.

~Joe

Offline campbmic

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Re: Resurrecting A Very Sad 1975 CB550
« Reply #2 on: January 06, 2010, 09:53:33 PM »
Unfortunately, it did not come with a title. However, I have a CX500 parts bike that I'm thinking I might just use the steering Vin tag and its title to drive around after the rebuild is done, until I get my title worked out.

Anyways, I did some more work on the bike today and got pretty far I do believe! I pulled the engine using the lay the bike over method which I definitely recommend, its very hard and dangerous to lift engines! I found a nice little place on my work bench to keep the engine and put some wood underneath.



After I had the engine in a nice place I proceeded to take off the valve cover. Note that you have to take the breather cover off and remove the four screw under the breather cover before you can take the valve cover off!







All of the exterior engine parts are super nasty I'm planning on using a home built baking soda blaster that I've seen on the site to remove all of the dieing chrome. Is this a good idea? Also, after I've done that do I need to use a clear coat finisher or should I paint the engine with some sort of high temperature chrome paint? I want it to be super shiny just like it came off the assembly line.

After I took the valve cover off things began to get interesting. To remove the cam shaft the first thing you do is remove the two screws connecting the cam shaft to the cam chain sprocket.



Then apparently you are suppose to turn the cam chain adjuster screw a 1/4 of a turn clockwise and the cam chain should have enough room to slip out of the sprocket. I honestly spent about an hour trying to wiggle the darn cam shaft out. Finally I got the brilliant idea of taking the chain off the sprocket!



That allows just enough room to remove the cam shaft. After I took the cam shaft and sprocket out I tied the cam chain with a long piece of string so it wouldn't some how get sucked into the bottom end  :o

In order to take off the the cylinder head that holds the cam and valves you must first remove the intake ports that run from the carbs to the engine and the cam chain tensioner assemblies.





At this point in time you can remove the nuts (I think its 12 or 10) and two bolts which holds the head onto the engine block







After I took the head off I finally got a glimpse at my pistons! I had been suspecting #1 was burning some oil however, #1 and #4 both looked abnormally shiny



I can't completely remember but I believe the block just slides right off I don't think its held down by any bolts but I could very well be mistaken. After I took the block off I this is what I saw, I can definitely tell piston #1 and #4 look different from #2 and #3. I'm thinking they were burning oil does anyone feel the same way?









So basically, this is where I stopped for the day. I'm pretty confused because I've never actually done an engine rebuild before. I'm pretty scared about taking the pistons off the rods and continuing into the bottom end. Do you guys feel that for my trip it would be necessary to check out the bottom end? I didn't really have any transmission issues when I was able to ride it. I'm planning cleaning out the fuel pump filter but thats about it so far unless anyone has any advice.

Furthermore, I really want to shine the crap out of the cases to make the engine look brand new. How can I do this without splitting the cases?

Lastly, now that its all torn down I need to know what my next steps should be. I'm guessing I should check the pistons and rings to see if they need to be replaced. Then check the cylinder walls to see if they need to be honed. What are the steps in doing this? Any other advice is greatly appreciated on what else I should do while I'm in here!

Thanks to anyone who is willing to help!
« Last Edit: January 06, 2010, 11:59:56 PM by campbmic »
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traveler

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Re: Resurrecting A Very Sad 1975 CB550
« Reply #3 on: January 06, 2010, 09:59:15 PM »

WOW!  That's alot of work for someone who has never touched a motor before!! :o

Ensure you have manual.

Label and bag all the parts as you disassemble.

GOOD LUCK!

~Joe


Offline campbmic

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Re: Resurrecting A Very Sad 1975 CB550
« Reply #4 on: January 06, 2010, 10:43:29 PM »
Thanks Traveler! It was pretty easy to be honest with you, hopefully this thread can help some others with some basic info. If anyone could answer the questions I have it would be really helpful!

I ordered a seat cover so I guess I will work on that and the frame until I can figure out what my next engine move is! Also, I'm really glad that after today I finally know whats SOHC means =)
Its hard to be wrong when you know nothing!

joec3613

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Re: Resurrecting A Very Sad 1975 CB550
« Reply #5 on: January 07, 2010, 04:35:00 AM »
Removing the pistons is easy, just remove the rings. Make sure you don't loose them since they can shoot out if you don't have a good grip on them! Get ready to start ordering lots of parts! Good luck!

Offline campbmic

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Re: Resurrecting A Very Sad 1975 CB550
« Reply #6 on: January 10, 2010, 11:14:27 PM »
Well I was finally able to get some time to do some more work! I decided for the next leg of my rebuild I would need to start by going to harbor freight to pick up some goodies!



I then proceeded to measure the cylinder bore with the telescoping gauge set and the 2"-3" micrometer. I figured that was the best place to start since I would know whether or not I needed to have my cylinders bored after measuring. It was a pretty simple process. First expand the telescoping gauge inside the cylinder then measure the length.





Unfortunately this was an SAE micrometer, I really don't like measuring in inches but I guess I had to.I measured each clyinder a total of thirty times. The first ten at the top of the cylinder (A) the next ten at the middle of the cylinder (B) and the last ten at the bottom of the cylinder (C). Heres the table of measurements I recorded.

Cylinder #1
A: 2.298   2.3014  2.295   2.294   2.3005  2.302   2.302  2.302   2.3025   2.3015    Average = 2.299859
B: 2.302   2.303   2.301   2.303   2.3025  2.301   2.298  2.303   2.3025   2.3025     Average = 2.30185
C: 2.3025  2.302   2.302   2.302   2.299   2.3015  2.291  2.303   2.3015   2.301      Average = 2.30055


Cylinder #2
A: 2.302   2.302   2.3025  2.3004  2.2945  2.302   2.302  2.302   2.302    2.3025    Average = 2.30119
B: 2.3025  2.3025  2.3015  2.303   2.302   2.302   2.301  2.302   2.3025   2.30075 Average = 2.301975
C: 2.296   2.3035  2.305   2.302   2.3015  2.303   2.3025 2.3025  2.303    2.303     Average = 2.3022


Cylinder #3
A: 2.298   2.303   2.303   2.3015  2.2995  2.302   2.304  2.3035  2.303    2.304     Average = 2.30215
B: 2.302   2.3015  2.301   2.3015  2.302   2.3     2.303  2.301   2.2995   2.302      Average = 2.30135
C: 2.3015  2.3     2.303   2.301   2.3015  2.303   2.3015 2.302   2.3025   2.303     Average = 2.3019


Cylinder #4
A: 2.303  2.304   2.3035  2.3025    2.3035   2.303   2.3015 2.3     2.299   2.3035   Average = 2.30235
B: 2.302  2.3025  2.303   2.303     2.303    2.3035  2.3025 2.3035  2.3025  2.302  Average = 2.30275
C: 2.3025 2.3025  2.3     2.3035    2.3025   2.3025  2.3025 2.302   2.303   2.303  Average = 2.3024


I concluded that all of the averages fall well within the 2.307 serviceable limit. So I'm guessing the work in the engine block is done right?

After I finished measuring I got a surprise package at my door!



And just in time too I don't think my poor old seat could handle much more  :P



I stripped the old seat of the old leather and seat cushion. The seat pan was probably the rustiest thing I have ever seen on a motorcycle. So I sanded it down and did a nice rattle can job on it with a clear coat. I didn't care too much since it was just the bottom of my seat but I think it turned out very well. I put the new leather on and the new strap as well. One of the screws attaching the strap stripped out and wouldn't come out at all! I tried an easy out and everything. I resorted to drilling out the center of the screw then drilling the head off!

Before:


After:




I think its looking good so far!


After messing with the seat took the pistons and clips out and labeled them each in their own individual baggy
Its hard to be wrong when you know nothing!

Offline Frankenkit

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Re: Resurrecting A Very Sad 1975 CB550
« Reply #7 on: January 10, 2010, 11:35:43 PM »
The difference between 1/4 and 2/3 could be a spark issue.  That's not to say that you didn't need to re-do your head gasket (and check for bent valves while she's apart) the problem leading to their being darker and wetter-looking may lie elsewhere. I suppose now that you have the head apart you can replace the valve seals, which can leak and cause oil to trickle down into the pistons causing that wet look.  The other thing is that you may just have less spark on 1/4 or a weaker spark leading to incomplete combustion.

I'll try to offer what help I can. I started into my 650 like you did, maybe greener.  I'd never ridden a bike before, but found a 650 on craigslist for $450 that ran on two cylinders, and I decided to give it a shot.
;) 

Just keep at it and while you're new at it be very, very organized. Take lots of pictures, maybe even sketch things and make notes.  It's really easy to misplace little bits.  For my money, I'm also going to say that you'll do well to rebuild your carbs.  These 4-carb systems are VERY touchy, and with as much dirt in the lines as you described, it may take 2-3 thorough cleanings to get it all. Be sure to get some Brakekleen and use it to clean out ALL the little passages.  Try to remove the o-rings before you do that, but if there are some you can't get to, don't sweat it.  Brakekleen will blow them up a little but eventually they shrink back down to size again.
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